1. Field of the Invention
The present invention relates to a rotary machine, and more particularly, to a radial piston machine utilizing fluids under pressure.
2. Description of the Prior Art
In my United States application Ser. No. 809,914, filed June 24, 1977, there is described a radial piston engine utilizing fluid under pressure, wherein the pistons are mounted in cylinders, subject to oscillating movement, and a cam shaft mounts an eccentric cam having a rotary movement relative to the housing.
In accordance with a specific embodiment described in the U.S. patent application Ser. No. 809,914, the pistons abut against the eccentric cam by the intermediary of an annular ring journaled on the cam, and the annular ring is subject to follow a circular translation movement with respect to the housing in relation to the rotary movement of the shaft relative to the housing. The amplitude of the circular translation movement is essentially equal to twice the displacement of the eccentric cam off-center. This non-rotational circular translation movement of the annular ring is maintained by means of rotary members connected to the housing and to the annular ring. These members have a certain elasticity in order to compensate for the differences in the actual distances between their axes resulting from the tolerances of manufacture of the different parts.
However, even though such members or cranks or swivels have certain elasticity, the geometry of these members is adapted to each value of the eccentricity of the cam.
If it is desired to modify the eccentricity of the cam, for example, in order to modify the displacement of the cylinders of the machine and thereby obtain a completely new engine with a different cubic capacity while maximizing the number of common parts used in the engine, it will be necessary to provide new retaining means to control the ring which should be a function of the change in the difference in the crank axes caused by the change in the eccentricity of the cam.
It can be seen, therefore, that due to the weak elasticity of the known anchor or crank means for providing the circular translation movement to the ring, these are poorly adapted, in the case of a radial piston machine having an interior cam and a variable cubic capacity by controlling the variation of the eccentricity of the cam.